1. Technical Field
The present invention relates to a vacuum device for manufacturing a plasma display device, and more particularly to a vacuum device enabling high throughput.
2. Related Art
Plasma display devices that can form a large screen with thin structure have been attracting widespread attention in recent years. Reference numeral 101 in FIG. 9 represents"" the structure of an AC type plasma display device, and comprises a front panel 120 and a rear panel 130.
Electrodes 121 and 131 are respectively provided on the surfaces of the front panel 120 and the rear panel 130. The front panel 120 and the rear panel 130 have the electrodes 121 and 131 facing each other. Each of the electrodes 121 on the front panel 120 and the electrodes 131 on the rear panel 130 are formed slender shapes respectively. The electrodes 121 are arranged parallel with each other, and the electrodes 131 are arranged parallel with each other. The front panel 120 and the rear panel 130 are arranged parallel with each other. The electrodes 121 on the front panel 120 and the electrodes 131 on the rear panel 130 are arranged perpendicular to each other. The AC type plasma display device is comprised enable to selecting and applying voltages to appropriate electrodes among the plurality of electrodes 121 and 131 desired positions on the plasma display device 101 can be made to emit light.
The manufacturing process of the front panel 120 of the plasma display device 101 will now be described with reference to FIG. 8. First of all, a transparent glass substrate 141 is prepared (FIG. 8(a)). A transparent conductive film (for example, ITO film) 142 is then formed on this glass substrate 141 (FIG. 8(b)), and then a metallic thin-film 143 is formed (FIG. 8(c)).
The transparent conductive film 142 and the metallic thin film 143 are then subjected to patterning, and after an electrode 121 comprising a transparent electrode 144 and a supplementary electrode 145 has been formed (FIG. 8(d)), a transparent dielectric layer (for example, a low melting point glass layer) 146 is formed on the surface of this electrode 121 (FIG. 8(e)).
Finally, the glass substrate 14 is taken into a vacuum chamber where a protective film 147 of MgO is deposited on the surface of the transparent dielectric film 146 by vapor deposition (FIG. 8(f)), and the glass substrate 141 is ejected from the vacuum chamber and relatively positioned opposite to and parallel with a separately formed rear panel 130.
Next, the front panel 120 and the rear panel 130 are sealed, and any atmospheric gas remaining between the panel 120 and the panel 130 is evacuated so as to form a vacuum between the panel 120 and the panel 130. During this evacuation, the panel is degassed by heating and after that a voltage is applied to the panel to cause electric discharge and aging processing is carried out.
Next, electric discharge gas is introduced between the panel 120 and the panel 130, which are completely hermetically sealed to form the plasma display device, and performance testing is carried out.
However, with the manufacturing process as described above, the protective film 147 is temporarily exposed to the atmosphere which means that it is subjected to the effects of moisture and there is a problem of deterioration (MgO is altered to Mg(OH)2). Also, after hermetic sealing, since degassing and aging processing is carried out, evacuation must be carried out through small holes existing between the panel 120 and the panel 130. Consequently, it is necessary to prolong the time for which degassing by heating introduced and aging process is carried out, which lowers throughput.
The present invention solves the above described problems, and an object of the invention is to provide a vacuum apparatus that can manufacture a high quality plasma display panel.
In order to achieve the above described object, the present invention provides a vacuum device for manufacturing a plasma display device having a front panel and a rear panel, comprising a film deposition chamber for depositing a thin film on a surface of the front panel in a vacuum atmosphere, and an alignment chamber for relatively aligning the front panel and the rear panel in the vacuum atmosphere, wherein the front panel is conveyed between the film deposition chamber and the alignment chamber without being exposed to the atmosphere.
In another aspect of the present invention, the rear panel can be conveyed into the alignment chamber without passing through the film deposition chamber.
In a further aspect of the invention, when the rear panel is conveyed the alignment chamber maintains a vacuum atmosphere.
With the present invention, it is possible to also have a structure where an assembly line having a hermetic sealing chamber is connected to the alignment chamber, the relatively aligned front panel and the rear panel are conveyed from the alignment chamber into the hermetic sealing chamber without being exposed to the atmosphere, and gas is introduced between the relatively aligned front panel and the rear panel, to enable sealing.
It is also possible to have a structure where an aging chamber having a heating device located therein is provided in the assembly line, the relatively aligned front panel and rear panel are conveyed into the aging chamber before being sealed, the heating device is caused to generate heat while the inside of the aging chamber is being evacuated, and the front panel and the rear panel are heated in the state of being relatively aligned.
In another aspect of the present invention, it is possible to have a structure where an aging chamber having a power supply is provided in the assembly line, the relatively aligned front panel and rear panel are conveyed into the aging chamber before being sealed, electric discharge gas is introduced into the aging chamber while it is being evacuated, a voltage is applied to electrodes on the front panel and the rear panel by the power supply, and electric discharge is caused between the front panel and the rear panel.
In yet a further aspect of the present invention, it is possible to have a structure where an examination chamber having a power supply is provided between the aging chamber and the sealing chamber, the front panel and the rear panel having completed processing in the aging chamber are conveyed to the examination chamber before sealing, a voltage is applied by the power supply to electrode on the front panel and the rear panel while evacuating the examination room, and electric discharge is caused between the front panel and the rear panel.
The present invention also provides a method of manufacturing a plasma display device comprising the steps of conveying a front panel into a film deposition chamber, depositing a thin film in a vacuum atmosphere and then conveying the front panel to an alignment chamber without exposing the front panel to the atmosphere, relatively aligning the front panel and a separately conveyed rear panel inside the alignment panel and sealing the front panel and the rear panel with an electric discharge gas introduced between the front panel and the rear panel.
With the above described structure, the present invention conveys affront panel constituting a plasma display device into a film deposition chamber, and after depositing a thin film in a vacuum atmosphere it is conveyed to an alignment chamber without being exposed to the atmosphere and is aligned with a rear panel in a vacuum atmosphere. Accordingly, gaseous elements such as moisture etc. are not adsorbed into the thin film deposited in the film deposition chamber and the quality of the thin film is not degraded.
The rear panel can also be conveyed to the alignment chamber after degassing processing. In this case, the degassing time for the rear panel is longer than the time required for thin film depositation on the front panel, which means that if a plurality of rear panels are continuously subjected to degassing throughput will not be reduced.
After the front panel and the rear panel have been aligned, heating is applied in the aligned state without exposure to the atmosphere, and charging gas and sealing (hermetic sealing processing) is carried out following degassing of the surface or the front panel the surface of the rear panel arranged opposite to each other, which reduces the processing time. Performing degassing processing before sealing in this way is known as aging processing.
As well as performing aging processing by heating, it is also possible to perform aging processing by introducing electric discharge gas such as a noble gas between the front panel and the rear panel located in a vacuum atmosphere in an aligned state, applying a voltage to electrodes of the front panel and the rear panel, generating a plasma by electric discharge between the front panel and the rear panel, and carrying out aging processing by degassing due to the plasma.
It is also possible to perform aging processing using plasma after aging processing using heating.
Before carrying out the hermetic sealing, if a voltage is applied to electrodes of the front panel and the rear panel to cause light emission and examination carried out in the light emitting state, defective products can be identified without performing the sealing process.
According to the present invention as mentioned above, the front panel and rear panel are processed concurrently in a vacuum atmosphere for manufacturing plasma display device.